// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	int T=1;
//	cin>>T;
	while(T--)
	{
		int n,sz=0;
		double ans=0;
		cin>>n;
		vector<int> x(n+1),y(n+1);
		for(int i=1;i<=n;i++)
		{
			int z;
			cin>>x[i]>>y[i]>>z;
			ans+=z;
			sz+=z;
			ans+=sqrt((x[i]-x[i-1])*(x[i]-x[i-1])+(y[i]-y[i-1])*(y[i]-y[i-1]))/50;
		}
		ans+=sz/2.0;
		ans+=sqrt(x[n]*x[n]+y[n]*y[n])/50;
		int ret=ans/1;
		if(ret!=ans)ret++;
		cout<<ret;
	}
	return 0;
}
